1. Field of the Invention
The present invention relates to a spout unit having a tamper-evident (tamper-proof) function projected at a discharge position of a container used for a beverage, a seasoning and so on.
2. Description of the Related Art
Conventionally, various kinds of containers, for example, a flat bag, a gusset bag, a bottle and so on are known as a container to be filled with an inner content such as beverage, seasoning or the like. For example, as shown in FIG. 13, a container equipped with a spout unit 101 comprising a cap 102 and a spout 120 has been used in a wide field of commercial product.
However, when the container having the spout unit is accidentally or intentionally opened in a distribution process or a sales situation, virginity of product may be deteriorated or an inner content of product may be falsified. It is hard to judge if commercial value is damaged by appearance of the product. As a countermeasure, a spout unit having a tamper-evident (tamper-proof) function has been used.
As the spout unit having a tamper-proof function, a spout unit which is designed so that break of a seal of a cap can be easily judged visually from a separated condition of a tamper-proof ring, wherein the tamper-proof ring is connected to a lower end portion of peripheral wall of a cap body and a thin fragile portion is provided in a part of the tamper-proof ring so that the break of a seal can be easily confirmed visually once the cap is open, thereby, when the sealed cap is rotated in the unsealing direction, the thin fragile portion becomes a break part and breaks.
In a general structure of the spout unit having the tamper-proof function, a spout unit comprises a cap in which a tamper-proof ring having a claw part is connected with a lower end portion a peripheral wall of a cap body, and a spout having a ratchet engageable with the claw part of the tamper-proof ring. In a part of the tamper-proof ring, a thin fragile portion, which can be a break part when the cap is to be opened, is provided.
Upon opening the sealed cap of the spout unit having the above structure, firstly, the cap is rotated in the unsealing direction (anticlockwise rotation around an ax of the cap) with respect to the spout of the cap, thereby, the claw part of the tamper-proof ring engages with the ratchet of the spout. From this condition, when the cap is further rotated in the unsealing direction, tension which works in the circumferential direction of the tamper-proof ring occurs so that the thin fragile portion provided to the tamper-proof ring becomes the break part and breaks.
Japanese Patent Application Laid-Open (JP-A) No. 2001-233364 discloses a tamper-evident cap device wherein a positioning protrusion, which sets out a fix-completion position of the cap, is provided at a container opening, and a bridge portion is provided between a cap body and a tamper-evident ring so that the bridge portion is located lateral to the positioning protrusion; and wherein when the cap body is separated from a neck part of the container, the bridge portion is cut off, thereby, separation of the cap is easily visible.
JP-A No. 2004-51195 discloses an unseal confirmation structure of a cap, wherein claw parts are arranged so that when a claw part is in a position that engages with a ratchet, an other claw part is in a position that does not engage with the ratchet, thereby, the claw part and the ratchet are surely engaged and a V-formed cutout provided at a part of a tamper-proof ring becomes a break part to be separated.
JP-A No. 2005-271922 discloses a movable cap having a tamper-evident (tamper-proof) function, wherein a tamper-proof ring is connected underneath a cap body, a connection piece (thin fragile portion), which connects ring pieces constituting the tamper-proof ring, is provided at least at one part of the ring piece, and the connection piece becomes a break part to be separated when opened.
The tamper-proof ring is made of a flexible and easy-to-break material, normally plastic, and partially has one of more easy-to-break portions, which are low in strength, in the ring circumferential direction so that the claw part can go over the ratchet when screwing the cap into the opening to close, and the ring can be broken in the ring circumferential direction by tension when rotating the cap in the unsealing direction to remove the cap from the opening.
As such a cap equipped with the tamper-proof ring is screwed into the opening of the spout, the flexible tamper-proof ring is slightly subject to plastic deformation when the ring goes over the ratchet so that the ring diameter increases. Thereby, as shown in FIG. 14, the tamper-proof ring 110 descends in the right and left directions from the easy-to-break portion of the tamper-proof ring 110 so that the tamper-proof ring 110 is distorted moderately curving in convex when viewed edge-on. Hence, there is a problem of deteriorating commercial value in appearance.
The moderate curve in convex (slightly shallow arc) is naturally corrected if there is no gap between the lower-end portion of the tamper-proof ring 110 and a base 124 beneath the opening of the spout when the cap 102 is screwed to the lowest of the opening. However, in such a case that the gap is not secured, since the lower-end portion of the tamper-proof ring 110 and the upper surface of the base 124 of the spout are closely contacted when the cap 102 is screwed to the lowest of the opening and friction resistance increases upon unsealing, significantly strong force is needed to unseal, thus it is inconvenient.
Also, if no gap is secured between the lower-end portion of the tamper-proof ring 110 and the base 124 of the spout when the cap 102 is screwed to the lowest of the opening, the form of the tamper-proof ring is corrected when, after unsealing, the cap is screwed again into the opening to re-seal, which makes it difficult to distinguish whether the ring has already been broken or not. Therefore, it is likely that unseal-warning function of the tamper-proof ring 110 is not fully exhibited.
An object of the present invention is to provide a spout unit having a tamper-evident (tamper-proof) function so that it is easy to determine visually that a sealed cap is opened when the cap is unsealed, wherein strong force is not needed to open while modification of moderate curve in convex (slightly shallow arc) from an easy-to-break portion of a tamper-proof ring is corrected when the spout is sealed with the cap.